Identifying brown spots with Jade and lemon tree

Question

I am trying to grow a lemon tree from seed and after circa 1 month tree is almost 5cm tall. However, this weekend it rained roughly and i checked my plants. I found out that my lemon tree has white/brown spots on the leaves. Moreover, one leaf is dead at the bottom of the tree (it is marked with orange circle). Yesterday, I had sprayed some water with garlic (serves as a pesticide). Is this early blight?

Moreover, I have a Jade plant that I have been growing for around 1.5 months from a cutting. This cutting had brown spots on the leaves as you can see in the image. This weekend it had rained roughly and many leaves with the brown spots fall down but not the strong green ones.

Additional details: I use organic pesticides and fungicides such as garlic and baking soda. I haven't sprayed baking soda for the past 2 weeks now and I do not exclude that the brown spots grow on the lemon tree after in the last two weeks. The brown spots on the jade there were even there before I stopped spraying.

Answer 1

Brown spots on leaves are usually caused by these factors:

• soil is too wet too often which results in waterlogged soil, virus/fungus/bacteria attack the plant and dead spots are usually seen in the oldest leaves first
• too much fertilizer can raise the level of soluble salts in the soil and cause "burn"

• sometimes physical damage can cause dead areas

• I find it unusual to keep seedlings outside where they are rained on as you indicate. Normally you want to regulate the environment so they get a good start. This alone could cause soggy soil.

• The soil mix contains a slow release fertilizer which is supposed to release fertilizer when the coating is wet. If the soil is too wet too much fertilizer can come out.
• why are you spraying seedlings with garlic and/or baking soda? Spraying should be done when you see a problem.
• your soil mix looks to be full of bark. This is alright for citrus but retains too much water for jade plants that need a free draining soil.

I recommend:

• move the seedlings indoors
• ensure both have good drainage
• do not spray unless you have a problem
• re pot the jade plant in a free draining soil with more perlite or sand
• scrape off the slow release fertilizer

Check out the questions and answers about citrus here. As your seedling grows it will be a heavy feeder and can get some pests like spider mite and scale.